


Good Boy

by old_enough_to_know_better



Category: Stray Kids (Band)
Genre: Aged-Up Character(s), Alternate Universe - Not K-Pop Idols, Anal Fingering, Anal Sex, Blow Jobs, Bottom Lee Felix (Stray Kids), Daddy Kink, Dog Trainer Seo Changbin, Explicit Consent, Explicit Sexual Content, M/M, Not Beta Read, Oral Sex, Praise Kink, Self-Indulgent, Shameless Smut, Soft Dom Seo Changbin, Top Seo Changbin, We Die Like Men, You have to read this, felix is uhhh whatever you want, inspiration is everywhere, no glove no love kids, yes taylor
Language: English
Status: Completed
Published: 2020-10-18
Updated: 2020-10-18
Packaged: 2021-03-08 20:40:16
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,189
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27072862
Author URL: https://archiveofourown.org/users/old_enough_to_know_better/pseuds/old_enough_to_know_better
Summary: When his friends convinced Felix to get a dog, no one told him how important it was to train them them properly. He just needs to find the right dog trainer to mold Sunny into shape. But how do you make it through a lesson when you've got a praise kink bigger than a Great Dane and a trainer with more muscles than a pit bull?Felix is about to find out.
Relationships: Lee Felix/Seo Changbin
Comments: 24
Kudos: 299





	Good Boy

Felix grumbled as Sunny dragged him into the building. “Get a dog, they said. It’ll be great, they said.” And he remembered when he had first seen him, a tiny puppy ready for adoption. How could he not fall in love? His golden fur that they brushed on a regular basis. They finally had fetch down. Sunny was around seven months old and had reached his mostly-adult size. He had also become a monster. Okay, so Felix had been really lax about training him as a baby, and now he was paying the price.

“Sunny, come on, you’re an embarrassment!” Felix whined as Sunny pulled so hard on his leash that he was walking on his hind legs. “Just walk nice for once in your life!” Sunny turned back to look at him, tongue out, eyes shining.

It was at that moment that Felix noticed a man whose shoulders were unmistakably shaking with badly concealed laughter. He pulled up short, accidentally tugging Sunny back. Even though he was laughing at him, this stranger was gorgeous. He was so thiccc. Broad chest and shoulders, narrow waist, muscular thighs. Felix felt his face flush as he realized that he just checked this guy out in broad daylight, so his eyes snapped to his face. Oof, blue-grey undercut. Who the hell are you? Snap out of it, Felix!

The handsome stranger pushed off the wall he was leaning against and strode easily over to Felix. He smiled at him briefly before dropping down to his knees and asking, “Is this Sunny?” Felix nodded wordlessly. After greeting the dog, the man pushed back up from the floor and extended a muscular arm to Felix. “I’m Changbin Seo. I’ll be your trainer.”

💠💠💠💠💠

Felix was straight fucked. Well, not straight. And he wasn’t getting fucked. But he wanted to be. And by his new dog trainer at that. As Changbin went over the general rules and risks of the sessions, Felix could barely keep himself from drooling.

“So, here at A Place to Stay, we work on the principle of Positive Reinforcement. That means we reward for the behavior we want to see, and don’t reward for the behavior we don’t want to see. Understand?” Changbin was very good at talking, with his gravelly voice. Felix nodded.

“Good. We always want to mark and reward a good behavior when we see it. Marking, like Yes or Good, happens right away, and is followed by a reward, like a treat, praise, or play.” Felix nodded again.

“Let’s try a Focus exercise, since that seems to be one of Sunny’s weak spots.” Felix chuckled nervously. “Don’t worry, it’s really common! What I’m going to be asking is for Sunny to look at me and then I’m going to reward for that. It sounds easy, but with all the noises here, it can be really hard.”

Changbin crouched down to eye level with the dog, holding a treat about a foot to the side of his face. “Look at me.” He commanded. Felix couldn’t help it, he looked. After a few more seconds, Sunny’s eyes flicked to Changbin. “Good boy.” He gave him the treat as something twisted in Felix’s stomach. They tried a few more times before he turned the reins over to Felix to practice. Within a few minutes, Sunny was offering eye contact on his own, and Changbin was wearing a beaming smile. “Who’s a good boy?” He asked.

Felix felt warm. He laughed awkwardly. “He is, isn’t he?”

Changbin quirked an eyebrow, but continued without a word about it. “Let’s work on his walking now. I want to show you something.” He pulled a few straps of nylon out of a box and said, “Tada!” Felix tilted his head. “It’s an EasyWalk. It’s going to change your life.” Again, he crouched down to the dog. “Let’s get this harness on you, boy.” Felix suddenly found the air harder to breathe. While Changbin adjusted the strappy harness, and got a few doggy kisses, Felix willed his breathing back to normal. He also absolutely did _not_ check out the trainer’s ass when he stood up. “Let’s take him for a few laps.”

Felix had to admit, he was right. That harness was amazing. The way it redirected momentum completely changed the dynamics of the walk. The dirty images it put in his head of the man walking beside him didn’t hurt either. They did make it very difficult to look him in the eyes, though. As they walked, Felix discovered that Changbin had been training for a little over five years, and was only two years older than himself. He had a Border Collie at home, as well as a Pekingese, and a cat that thought it was a dog, and was trained like one.

He was shocked to find out that an hour had passed by the time they got back to the small training room, and their session was coming to an end. He and Changbin shook hands, and one last time, Changbin turned to Sunny. “Are you going to be a very good boy for Daddy?” Felix bit the inside of his cheek as he felt his dick twitch, and he could have sworn he saw Changbin smirk. “Perhaps I’ll see you two again?” Felix nodded as they left the room. Sunny was definitely walking better. Maybe this training thing was worth something after all.

💠💠💠💠💠

Felix awoke to an email from the training center. He was confused, because Changbin was asking him to meet, as soon as he could, at a café of all places. He was pretty sure this wasn’t part of the training program. Fortunately, he was free at the suggested time, so he shot a quick email back, then went about his morning routine. He let Sunny out to go potty quickly, then shut him back in for his shower. He wondered how Changbin managed with three needy animals as opposed to one as he stripped his clothes off. At the thought of the trainer, his cock began to stir to life. He considered ignoring it, but then remembered that he was meeting with the object of his desires in just a few hours, so he decided that the best course of action was to get rid of it.

In the shower, with hot water pulsing on his back, Felix let his fingers explore his body while he pretended they belonged to the trainer. Within just a few minutes, he was crying his release with Changbin’s name on his tongue. He was well and truly fucked.

Felix tugged the sleeves of his sweater further over his hands as he entered the cute little café. He had never been here before, which was a surprise, given how much of a sucker for overpriced hand-crafted drinks he was. He decided to get his drink before looking for Changbin. By the time his mocha frappe with extra sprinkles was done, he had spotted the back of the other’s head. And his shoulders, inconveniently clad in a leather jacket. The barista cleared her throat as she thrust the cup in Felix’s direction. “Can you just take this?” Felix flushed, but took the cup and mumbled an apology.

He walked as steadily as he could over to Changbin’s table, sliding smoothly into the seat across from him. “Fancy meeting you here.” He joked.

Changbin chuckled before taking a sip of his coffee. “I’m really glad you could make it.” He set his steaming up down and folded his hands together. After a deep breath, he continued. “I don’t think I can be your trainer anymore.”

“What?!” Felix sputtered. This was a disaster. “But Sunny learned so much! _I_ learned so much!”

Changbin shook his head. “I’m really glad to hear that.” Oh god. Felix swallowed hard. This was about him. Changbin had noticed and was disgusted. Felix’s head was spinning. “But I still can’t take any more of your money for lessons.”

“But I-“

Changbin leaned forward in his chair. “It’s unethical to work with this kind of conflict of interest.”

“I’m so sorry, I-. Wait, what?”

Changbin chuckled, and Felix found that he really like that sound. “Unless I read things absolutely wrong?” He raised his eyebrows, and Felix shyly shook his head. “Then, yeah, it’s not your money I’m interested in.”

“O-oh.” Felix was sure he was bright red by now.

Changbin smiled, something that Felix decided should be illegal, and continued, “Anyways, it’s my day off, so I don’t know what you’re up to…”

“Nothing!” Felix interjected. “I mean, I don’t have any plans. It’s just me and Sunny today.”

“Perfect.”

After chatting a little while longer, Felix found himself at the door to his apartment with Changbin by his side. He tugged his bottom lip through his teeth before asking, “Hey, you wanna come in?”

Changbin laughed. “I thought that was the plan. I kinda miss Sunny, y’know.” Felix fake-pouted as he unlocked the door. Inside, they heard the golden retriever whining.

“Oh, you big baby, I’m home, and I brought a friend!” Sunny woofed in response.

“Sunny, remember me?” The dog whined and spun in circles. “I think that’s a yes.”

“You gotta go out, buddy?” At the answering bark, Felix let the golden out into the small fenced yard that was attached. He felt Changbin slip around behind him and one hand graze lightly against his waist. He shivered at the touch. Changbin just walked past him though, taking his touch away.

He looked at the pictures that Felix had hanging on the wall. A few of Sunny, a few group shots of him and friends. No childhood photos, and no family. He turned back to Felix, who was calling Sunny back in.

“Now, be a good dog, and don’t eat anything. Don’t get into trouble. I’m gonna leave out your snuffle mat, and your stuffed Kong, _and_ your treat ball. Please just don’t make a mess.” Felix begged the dog. He set out the toys before straightening up and wiping his hands on his jeans. “Now, where were we?” He asked nervously.

Changbin smiled softly. “You’re so good to him.” Felix felt a flush on his neck. He swore the room was getting warmer. “Come here.” Felix willingly complied, shuffling forwards until he was within an arm’s reach of the older. “Do you want me to take my jacket off and stay a while?” He asked. Felix nodded, almost regretfully. That leather jacket looked damn good on him. But he also knew what lie beneath its well-worn surface.

Changbin slid the jacket down his shoulders, pecs and biceps bulging. Felix felt his mouth go dry. He couldn’t believe this was happening. Changbin tossed the jacket over the back of a chair as Felix looked him up and down. His current outfit was much more snug that what he was wearing at the training center, right now in a plain white tee and tight ripped jeans. Felix was pretty sure he was face to face with a god.

He didn’t even realize he was leaning in until Changbin took a step forward and they were face to face. “Is this what you wanted?” He nearly whispered, warm breath ghosting Felix’s lips. Felix gave the slightest of nods. “Do you deserve it?” Changbin asked.

“Yes.” Felix nearly whined. He was on the brink of desperation. Just when he thought he would be denied, he felt the soft touch of the other’s lips against his, ever so gentle at first, but quickly gaining force. Felix hooked his fingers into the muscles in Changbin’s shoulders, while the older’s hands were drawn to the younger’s platinum hair. He gave a gentle tug, and Felix moaned. Changbin wasted no time, using that opening to sweep his tongue into the taller’s mouth, tasting his warmth, leading him in a passionate dance. Felix could feel his knees weakening, especially as one of Changbin’s hands fell from his hair to toy with the hem of his sweater. His knuckles brushed the waistband of his jeans, occasionally making contact with his skin, sending licks of fire up his body.

Felix finally broke away for air, gasping. He could feel how swollen his lips were, bruised and spit-slick. He really didn’t care. Not with the way Changbin was looking at him. “Take this elsewhere?” Changbin asked with a glance at the dog, who was currently occupied with his snuffle mat. Felix nodded shakily, grabbing Changbin’s hand and leading his to the bedroom.

Once inside the room, Changbin pressed Felix against the door and mouthed at his neck. “God, you’re so sweet.” He moaned in between kisses. “I could just eat you up.”

Felix groaned. “Ungh, please!” He could feel Changbin’s grin as he bit down on the juncture between his neck and shoulder. Felix threw his head back and gave a moan that would make a porn star proud. He pushed Changbin away, panting. Changbin frowned, his eyebrows knitting together. Felix just smiled, reaching down to his waist, grabbing the hem of his sweater.

As he pulled it up and over his head, he kept eye contact with Changbin, whose eyes shone. “Are you gonna be good for me?”

Changbin nearly had to lean in to hear the answering, “Yes daddy.” But it had the desired effect. He groaned, pulling his own shirt off and unbuttoning his jeans. Felix felt his mouth water at his first glimpse of Changbin’s naked torso. He desperately wanted to trace the tattooed line of pawprints running up from the front of his pants, along his ribs, and up his chest with his tongue. Maybe he would.

“Get down here.” Changbin rasped out, shoving his jeans and underwear partway down his thick thighs. Felix watched as his heavy cock sprung free before dropping to his knees, crawling the short distance between them. “Start being good.”

Felix licked his lips as he stared at the dick in front of him. Like its owner, it was broad and proud, average in length, but oh, the girth! Felix stretched his jaw once before placing a kitten lick on the flared tip. Changbin grunted, moving a hand to Felix’s head. He smiled, licking a broad stripe up from the base to the tip before taking just the tip in his mouth. He suckled for a moment, wet and sloppy, pulling a deep groan from the man above him. He bobbed his head down, taking more of the thick cock, feeling the stretch at the back of his mouth. Changbin’s hand tightened in his hair, and Felix went a little farther. Breathing purposefully through his nose, he relaxed his throat, sinking deeper, until his nose nestled in the trimmed curls at the base. He pulled his hands gently against the backs of Changbin’s thighs, looking up at him with hope in his eyes.

The message got through. “Oh, what a good boy,” Changbin moaned as he fisted Felix’s hair. He pulled back with his hips, then gave a short, slow thrust forward. Felix closed his eyes, throat taking the intrusion with no problem, so Changbin sped up. Felix was a mess, tears at the corners of his eyes, spit and precum dripping from his mouth, rock hard cock straining against his jeans. He wouldn’t touch himself, though. Not until Changbin said so. “Oh my god, here it comes!” Changbin pulled out, and Felix opened his mouth. He was rewarded with ropes of white painting his tongue, lips, and chin. He held it in his mouth as Changbin wiped the excess off his face and into his mouth. With one dirtied finger against his tongue, he commanded, “Swallow.” Felix whined as he obeyed.

Changbin hummed as he brushed his thumb over Felix’s lower lip. “So pretty for me. You did such a good job.” Felix grinned shyly, looking up at him from underneath his eyelashes. “Come up here.” Felix pushed off the carpeting, rising to his feet. He was rewarded with Changbin’s warm hands on his hips, thumbs toying with the waistband. “Off.”

“Yes daddy,” Felix answered softly when Changbin tugged at his belt loops. He almost stumbled forward into the other, but caught himself in time. He whimpered when his fingers brushed his bulge as he pulled down his zipper. Shimmying the jeans over his ass and down his legs, Felix could feel Changbin’s eyes on him.

They took a moment to just look at each other before Changbin jerked his head in the direction of the bed. Felix climbed on top of the sheets, pushing the covers to the foot of the bed. Changbin kneeled in the messy nest of blankets and looked up at the blonde. “Color, baby?”

Felix melted at the pet name. “Green. So very green.”

“Good. Where do you keep the lube?” Felix flushed, leaning over to his bedside table. From the bottom drawer, he pulled out a bottle of lube that was definitely less than full, as well as a few condoms. “Good boy. I didn’t even have to ask.” Changbin clicked open the bottle and gave a sniff. “Strawberry? Nice.”

Felix blushed and looked away. Though he was prepared, recently the majority of the action he had been seeing was solo. It had been a while since he had had a partner, and he was nervous. Especially one that looked and acted like Changbin. He ticked all Felix’s boxes and pushed all the right buttons. If Felix’s type had an entry in the dictionary, Changbin Seo’s picture would be next to it.

Especially as he directed the younger man to turn over so he was on his hands and knees, facing away from him. Felix arched his back as Changbin ran his hand over the knobs of his spine, ending with a sharp smack on his ass. Felix hissed in a breath at the sting, which was quickly being caressed away. Changbin gathered the meat of one cheek in his hand, his thumb sweeping along the seam, dangerously close to the entrance. Felix tried and failed to hold back a whimper.

“Ah ah, I thought you were going to be a good boy.” Changbin gave a quick swat to the other cheek with his free hand while he still brushed at Felix’s crack.

“’M trying. Trying real hard. Want you.” Changbin laughed, a warm sound that made Felix feel fuzzy deep within his stomach. “Please, daddy.”

“Since my baby boy asked so nicely.” Felix whined as Changbin’s hands left him, but soon heard the distinct sound of lube being squirted out and rubbed on his fingers. Before long, Changbin’s hand was spreading his cheeks wide, and Felix gasped as the still-cool liquid hit his rim. The older circled a few times, applying light pressure, before finally delving a finger in. He was met with little resistance. “Did you finger yourself already, dirty boy?”

“I was thinking ‘bout you. Couldn’t help m’self.”

“Filthy.” Changbin scolded as he inserted another finger alongside the first. Felix squirmed as his fingers just narrowly missed that special spot inside of him. He was rewarded with another spank with Changbin’s clean hand. “Good boys hold still.” He scissored his fingers to drag along Felix’s walls as he pulled out, and Felix moaned, trying his best to stay put. He fisted his hands in the sheets near his shoulders, scrunching his face at the stretch as Changbin slid in a third finger.

“That’s better.” Changbin praised as he crooked his fingers, finally brushing Felix’s prostate. The younger cried out, jutting his ass back to try to increase the sensation. “My good little slut. Still green?”

“So green, so good, please fuck me! I’m ready.”

“You think so?” Felix nodded, his cheek rubbing against the sheets. Without turning around to look, he could hear the tearing of a foil packet, and the telltale squelch of rubber being rolled down on Changbin’s cock. Peering over his shoulder, he could see Changbin fisting himself back up to full hardness. He let his head fall back against the mattress.

Changbin leaned over him to purr in his ear. “Sure you’re ready, baby?” Felix nodded again, biting his lip. “Words, baby. I need to hear it.”

“Yes!” He quickly gasped. “Please, I need you in me!”

Changbin chuckled as he brushed the head of his cock against Felix’s rim. Felix arched his back, pressing back against him. Changbin laid a hand on the small of his back to hold him still. Slowly, he pushed through the resisting muscle.

Felix was sure he would never be the same. As his walls parted to make room, his breath became increasingly ragged. Changbin rubbed circles into his sides with his thumbs as he bottomed out, resting his forehead in between Felix’s shoulders for a moment. “Babe,” he panted, “tell me when I can move.”

Felix took a deep breath, then gave the go ahead. He groaned as Changbin slowly pulled out until just his head was inside, catching on his rim, then he thrust back in, much quicker this time. As Changbin repeated the action, Felix rolled his hips, meeting his thrusts at a different angle to stimulate his prostate. He whined, high and loud. Changbin ground into him, gripping tight to his side.

“Right there?” He asked, pounding in again. Felix could only whimper in response. “Oh my god, you’re so tight.” He moved one hand to Felix’s shoulder, causing him to arch up on his elbows, curving his back. His grip was deliciously tight, his hands large and burning hot. Felix could feel fire licking though every inch of his skin, radiating from every point of contact. Changbin was burning him alive from the inside, and he wanted more.

He told him as much, and the older man picked up the pace, making Felix cry out as he abused his hole. The room was filled with the sounds of skin slapping together, punctuated by groans and gasps. Felix could feel the telltale curl of warmth in his belly, and began to reach one hand down to wrap around his neglected cock, but Changbin brushed it out of the way. “Let me, baby, you’ve been such a good boy.” Felix gasped when his hand, still wet with lube, made contact. His fingers easily wrapped around, and began stroking a gentle rhythm. Within seconds, he picked up the pace, until Felix was near tears.

“Let go, just let it out, then I’ll fill you up like you deserve.” Changbin growled deep in his throat, and Felix had no choice but to listen. Even if he didn’t want to, which he did, his body was already shuddering with the beginnings of his orgasm, coming hard in thick white ropes across his stomach and his bed. Changbin’s hand did not escape unscathed, and without losing his pace, he brought his fingers to Felix’s mouth and commanded him to suck. As soon as the younger man was swallowing around the soiled fingers, Changbin was filling the condom, hips stuttering as he pulsed his release. 

They stayed like that for a moment more, basking in the afterglow, before Changbin slowly pulled out, both groaning at the loss of sensation. Changbin neatly tied off the condom, and asked for the bathroom. Felix gave vague directions, to which Changbin chuckled and replied, “The room with the toilet, got it.”

The last thing Felix remembered before drifting off to sleep was being wiped down with a warm, soft towel.

💠💠💠💠💠

It was very late when Felix woke. He was sore all over, especially his ass, but couldn’t help thinking it was worth it. He looked over at the other side of the bed, and frowned to find it empty and cold. Checking the room, there was no sign of another person. Well, fuck. Not even a note.

He trudged his way out into the main living area to mope. At least he could have his dog for company, however much good that would do.

When he got to the living room, he stopped short. Sunny hadn’t made a mess, even though he had been out of his crate for several hours. In fact, he was completely out of trouble, playing on the floor with what Felix could only describe as an angel. Floofy blue-grey hair, unstyled across his forehead, no makeup, wearing Felix’s baggiest sweats, Changbin knelt on the floor, apparently trying to teach Sunny how to roll over. Felix’s heart grew three sizes that day.

“I thought you couldn’t train Sunny anymore?” He asked quietly.

Changbin looked up sheepishly, caught in the act. “I never said that. No, I told you I couldn’t take your money.” He got distracted cheering for the dog as he successfully rolled over, before returning to the conversation. Rubbing a hand on the back of his head, he continued, “Well, I didn’t expect to go this far, but I like you. I guess that’s kind of obvious. But like, for real. And I—“

“Changbin.” Felix giggled. “Will you go on a date with me?”

The older’s eyes widened at his forwardness, but his expression soon morphed into a grin. “Only if you promise to be a very good boy.”

**Author's Note:**

> Once again, thank you for reading my self-indulgent garbage!
> 
> In case you hadn't guessed, yes, I am a dog trainer in my day job! Also yes, I have a praise kink. Also also yes, I have a Changlix kink.
> 
> Please give kudos and comments if you liked it, or leave constructive criticism if you feel like it.
> 
> Also, scream at me on twitter, mostly to make me post more.  
> @minnisoldenough


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